In proximity exposure, a mask and a workpiece are arranged opposing each other with a predetermined gap therebetween, the mask is irradiated with light for pattern exposure, and the mask patterns of the mask are exposed and transferred onto a photoresist of the workpiece by a photolithography method. In recent years, miniaturization and high integration of patterns has been advanced, and patterning at a resist pattern pitch equal to or smaller than a resolution limit (resolution) of the resist is required.
Patent Document 1 discloses a technique capable of exposing at a pitch equal to or smaller than a resolution limit of a resist, in which a first mask having openings arranged at a pitch of 2× and a second mask having a pitch of 2× and displaced by one pitch with respect to the openings of the first mask with respect to a pitch x of resist patterns are prepared, and the first mask and the second mask are sequentially arranged one by one on the resist to perform exposure.